Automated test sequence editor and engine for transformer testing

ABSTRACT

A system and method for creating, editing, and/or executing a test program for testing a transformer is provided. The system includes an input that allows the user to select the desired test instructions and pre-existing sequences of test instructions to create or edit a test program having a sequence of test instructions. The processor executes the test program by generating commands that are performed in a predetermined order.

FIELD OF THE INVENTION

[0001] The present invention relates in general to transformer testingand, more particularly, to automated test equipment for transformertesting.

BACKGROUND OF THE INVENTION

[0002] Transformers are tested by their manufacturers and by electricutilities. The tests may include polarity, phase relation, core loss,load loss, and transformer ratio. However, there is no universal testingprocedure followed by all testers. Different standards are followed andsometimes transformer manufacturers implement their own custom testsequences. Many times, the customer requires the manufacturer to followa certain test sequence, and with many different customers, changingtest sequences after every order is not an easy task for themanufacturer's transformer testing facility. Moreover, different systemsare typically needed to implement different tests.

[0003] Automated testers test transformers according to a test programhaving a predetermined sequence of test instructions. In other words,the test program executes a fixed sequence of test instructions thatcannot be edited or is extremely difficult to edit. For example, if thetest program selects a transformer test which is programmed to first runa winding resistance test and then a voltage ratio test at a certain setof parameters, then each time the transformer test is selected, thewinding resistance test is performed first and the voltage ratio test isperformed second. Thus, the sequence of test instructions is arrangedsuch that a sequence of test instructions specifying a windingresistance test is listed before a sequence of test instructionsspecifying a voltage ratio test. The disadvantage of having a testprogram with a fixed sequence of test instructions is that the user doesnot have the flexibility of editing or creating a particular sequence tooptimize the transformer test program.

[0004] Therefore, an automated transformer tester having a sequenceeditor to edit or to create customized test programs, along with a testengine that can implement a variety of tests and test sequences, isdesirable. It is further desirable to have one testing system that canperform multiple tests without the need for different controllers orsystems.

SUMMARY OF THE INVENTION

[0005] The present invention is directed to a transformer test sequenceeditor for transformer testing that enables a tester to implement anytest sequence, whether standard or customized, with any test parameters.A transformer test sequence engine is also provided that enables atester to perform tests created using a test sequence editor and tomonitor the test results. The automated test sequence editor and engineallows the transformer tester to edit a test sequence in any order. Thetester can also modify any or all of the test parameters.

[0006] According to an embodiment of the invention, a system for testinga transformer comprises a processor comprising a transformer test engineadapted to execute a transformer test sequence; a controller coupled tothe processor to output control commands; a switcher coupled between thecontroller and the transformer to switch power to the controllerresponsive to the control commands; and a metering system coupledbetween the transformer and the processor to receive measurements fromthe transformer and provide the measurements to the processor.

[0007] According to aspects of the invention, a memory device is coupledto the processor for storing transformer specifications. A memory devicemay also be provided for storing the transformer test sequence.

[0008] According to further aspects of the invention, a test sequenceeditor allows customization of the transformer test sequence.

[0009] Another embodiment of the present invention is directed to amethod for testing a transformer comprising connecting the transformerto a processor comprising a transformer test engine; loading acustomized transformer test sequence into the processor;

[0010] and executing the customized transformer test sequence with thetransformer test engine.

[0011] According to aspects of the invention, results of the executionare provided to the processor along with transformer specifications tothe processor. It is determined whether the transformer passesresponsive to the results and the transformer specifications.

[0012] A further embodiment of the present invention is directed to amethod for creating or editing a customized transformer test programcomprising selecting at least one test instruction or pre-existingsequence of test instructions from a plurality of transformer testinstructions; providing at least one associated parameter for each ofthe selected test instructions or pre-existing sequence of testinstructions; and defining an order of execution of each of the testinstructions.

[0013] According to aspects of the invention, the order of execution ofeach of the test instructions is stored, and the test instructions areexecuted in accordance with the order. A transformer test sequence isgenerated based on the order.

[0014] The foregoing and other aspects of the present invention willbecome apparent from the following detailed description of the inventionwhen considered in conjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

[0015]FIG. 1 is a block diagram of an exemplary system in accordancewith the present invention used for testing transformers;

[0016]FIG. 2 is a block diagram of an exemplary processor in accordancewith the present invention;

[0017]FIG. 3 is a flow chart of an exemplary method of creating orediting a customized transformer test program in accordance with thepresent invention;

[0018]FIG. 4 is an exemplary transformer test sequence editor screenshot, with an exemplary transformer test program, in accordance with thepresent invention;

[0019]FIG. 5 is an exemplary applied test setup screen shot inaccordance with the present invention;

[0020]FIG. 6 is an exemplary induced overvoltage test setup screen shotin accordance with the present invention;

[0021]FIG. 7 is an exemplary load test setup screen shot in accordancewith the present invention;

[0022]FIG. 8 is an exemplary magnetizing current test setup screen shotin accordance with the present invention;

[0023]FIG. 9 is an exemplary megger test setup screen shot in accordancewith the present invention;

[0024]FIG. 10 is an exemplary no load test setup screen shot inaccordance with the present invention;

[0025]FIG. 11 is an exemplary ratio test setup screen shot in accordancewith the present invention;

[0026]FIG. 12 is an exemplary resistance test setup screen shot inaccordance with the present invention; and

[0027]FIG. 13 is an exemplary test engine screen shot in accordance withthe present invention.

DESCRIPTION OF EXEMPLARY EMBODIMENTS AND BEST MODE

[0028] The present invention relates to a transformer test sequenceeditor for transformer testing that enables a tester to implement anytest sequence, whether standard or customized, with any test parameters.A transformer test sequence engine is also provided that enables atester to perform tests created using a test sequence editor and tomonitor the test results. The automated test sequence editor and engineallows the transformer tester to edit a test sequence in any order. Thetester can also modify any or all of the test parameters. After creatingthe test sequence using a graphical user interface, for example, thetester can save the sequence.

[0029]FIG. 1 is a block diagram of an exemplary system in accordancewith the present invention used for testing transformers. It isappreciated that the present invention may also be used to test othertypes of electronic equipment. The transformer testing system 100includes a processor 110, memory devices 115, 120, a controller 130, aswitcher 140, and a metering system 150. A transformer 200 that is to betested is disposed between the switcher 140 and the metering system 150.The switcher 140 is coupled to a power supply 145 and provides power tothe transformer 200 during the test. The memory devices 115, 120, thecontroller 130, and the metering system 150 are coupled to the processor110 via a bus 190. In one embodiment, the processor 110 is an IBMcompatible personal computer having a Pentium processor manufactured byIntel Corporation and the bus 150 is a general purpose interface bus.

[0030] As shown in FIG. 2, the processor 110 preferably includes a CPU111 coupled to an input/output device 112, a memory device 113, and adisplay 114 via a data bus 117. The input/output device 112 includesalphanumeric oriented input/output devices such as a keyboard or a mouseand real-time data-oriented input/output devices such asanalog-to-digital converters and digital-to-analog converters. Thememory device 113 includes random access memory (RAM), read-only memory(ROM) and mass memory devices such as a disk drive. The display device114 can be a computer terminal or monitor, for example. The data bus 117is used for communication between the CPU and the memory or theperipheral devices.

[0031] In accordance with the present invention, the processor 110includes a test sequence editor that allows the user to customize atransformer test program having a sequence of test instructions by entryof input commands.

[0032] The memory devices 115, 120 can be RAM, ROM, or mass memorydevices such as a disk drive, and can be separate or reside within thesame memory device. Preferably, the memory device 115 comprisestransformer specifications, and the memory device 120 receives andstores the results of the transformer test, which can be used for futurestudy and analysis.

[0033] The switcher 140 is controlled by the controller 130 to providepower from the power supply 145 to the transformer 200 being tested. Themetering system 150 receives the measurements from the transformer 200and provides the measurements to the processor 110. The processor 110processes the measurements and stores the result(s) in the memory device120 or elsewhere.

[0034] A transformer test program can be customized by creating orediting a new sequence of test instructions from individual testinstructions or other pre-existing sequences of test instructions viathe test sequence editor residing in the processor 110. A sequence oftest instructions comprises test instructions that are executed in apredetermined order. A user can create sequences for testing atransformer and store these sequences for future use, either as astand-alone test sequence or as a portion of a larger test sequence.Therefore, individual test instructions as well as pre-existingsequences of test instructions can be used as building blocks to createor edit a transformer test program. In other words, a new sequence oftest instructions may operate as its own test program or may be used asa building block for another test program. Thus, the sequence editorprovides the flexibility of creating new sequences of test instructionsfrom a combination of existing test instructions and pre-existingsequences of test instructions. Note that a test instruction includes aninstruction that is executed by the processor to either control someaspect of the hardware of the testing system or to process data.

[0035] After the user creates or edits the test program by selecting thedesired test instruction or pre-existing sequence of test instructionsalong with associated parameters via the input/output device 112, thetest program is saved as a file in the memory device 113 or elsewhere.

[0036] Test instructions that can be used in building test sequencesinclude, but are not limited to, winding resistance test, voltage ratiotest, magnetizing current test, load test, and induced overvoltage test.Additional tests are described below. Parameters that can be set to acton these tests include, but are not limited to, test voltage, testduration, ramp profile, and temperature range, as further describedbelow.

[0037]FIG. 3 is a flow chart of an exemplary method of creating orediting a customized transformer test program in accordance with thepresent invention. Commands are inputted into a processor at step 300 inorder to create or edit a test program. More particularly, the userselects a test instruction or a pre-existing sequence of testinstructions by inputting entry commands into the processor 110 via itsuser interface. At this point, the user inputs or selects the tests tobe performed by entering commands or objects via a graphical userinterface, for example. The user can prepare new tests or use previouslyselected, entered, and/or stored tests.

[0038] Next, at step 310, the user enters test parameters (such as testvoltage, test duration, ramp profile, and temperature range) to be usedduring execution of the test. Programmable test equipment is used undercomputer control to set the desired parameters and conditions for anyparticular test condition and to record the desired measurements. Atthis point, the tests are to be performed in the order in which theywere entered into the test program. This order can be changed, forexample, at step 330, described below.

[0039] At step 320, it is determined whether the user desires to selectadditional tests to be included in the test sequence. If so, processingreturns to step 300 until the user has entered all the desired tests andparameters. The user continues selecting and defining the order ofexecution of other test instructions and/or pre-existing sequences thathe wishes to incorporate into the transformer test program.

[0040] After the user has completed entry of the desired tests andparameters, at optional step 330, the user can re-define the order ofexecution of the selected tests within the test program (i.e., re-orderthe sequence in which the selected tests are to be performed). In otherwords, the user specifies when the selected test or pre-existingsequence of test instructions should be executed in relation to theother tests or pre-existing sequences of test instructions in the testprogram. In this manner, the sequence editor allows the user to specifythose test instructions or pre-existing sequences of test instructionsmost likely to cause a failure to be performed before other testinstructions or pre-existing sequences of test instructions which arenot as likely to cause a failure.

[0041] At this point, the user has created a customized transformer testprogram that is executable. The test program can then be executed viathe test engine, at step 400, to determine whether the transformerpasses or fails the customized test program.

[0042] The test instructions can be implemented in any computerlanguage. In one embodiment of the present invention, the testinstructions are implemented using LabVIEW software by NationalInstruments.

[0043]FIG. 4 is an exemplary transformer test sequence editor screenshot, with an exemplary transformer test program, in accordance with thepresent invention. The test sequence 405 includes various tests withparameters, in a particular order of execution. Parameters shown includeTV (test voltage), Tr (reference temperature), TM (temperature maximum),Tm (temperature minimum), M1, M2, M3 (measurements 1, 2, and 3), Tp(tap), TC (test current), TD (test duration), AT (automatic), R1, R2(ramp up), and Cr (correction).

[0044] Commands 410 include “new sequence” which allows a user to entera new sequence for testing, “open sequence” which allows the user toopen previously saved sequences and lists, and “save sequence” whichallows the user to save the format of the tests. After the “savesequence” command is selected, the user can activate the same test onother transformers or within other test sequences, by selecting it viathe “open sequence” command.

[0045] Test configurations 420 are provided to give selection access toa user. By selecting a test name, the test will be included in thesequence for editing and execution.

[0046] According to FIG. 4, the first test to be performed is the ratiotest with a maximum temperature parameter of 40° C., a minimumtemperature parameter of 10° C., with tap 1. Additional tests (andparameters) to be performed following the ratio test in the orderprovided are also shown. After executing the various tests, the systemcan determine whether the transformer passes or fails, or classify thetransformer into a particular grade or level of performance.

[0047] An exemplary applied test setup screen shot is shown in FIG. 5.The applied test tests the insulation of the magnetic field. A high ACvoltage is applied between the bushings and the ground. Either a highvoltage or a low voltage can be applied. The choice of which one is tobe used is available in the sequence editor screen, where the user canselect high applied or low applied.

[0048] With respect to FIG. 5, nominal BIL is the basic insulation levelof the bushings. The test voltage results by multiplying the basicinsulation level of the bushings by a user provided factor number, whichcan be entered via an input device such as the keyboard or a selectionon the test setup screen.

[0049] With respect to the test duration, the user may enter the amountof time the test is to last. The test duration is represented on a rampprofile 500 by the horizontal line 515 at 100% amplitude.

[0050] The ramp profile 500 is presented in the form of a curve. Thefirst substantially linear line 505, which runs from 0% to about 90%amplitude is the Ramp Up1 speed. The slope of the curve is steep,representing a rise in a relatively small time interval, and hence arise at high velocity. When the curve reaches about 90% amplitude, thespeed decreases. This second curve 510 has a less steep slope,representing a rise during a relatively large time interval. Once thecurve reaches about 100% amplitude, the ramp up speed becomes zero, atwhich time the test is performed. The horizontal line 515 represents thetest duration. Once the test is over, the ramp down begins at maximalspeed, represented on the curve by the negative slope 520. The curveeventually reaches 0% amplitude, and the particular test is over.

[0051] Ramp Up1 is the speed %/sec of the rise in amplitude towards theperformance of the test. The range is preferably between 0%/sec andabout 25%/sec, and is user selectable. This speed lasts until the curvereaches about 90% of the required amplitude.

[0052] Ramp Up2 is the speed of approaching the test, between about 90%amplitude up to about 100% amplitude at which the test begins. The rangefor the Ramp Up2 is preferably smaller than that of the Ramp Up1, so asto ensure a slower approach towards the test.

[0053] Temperature Max is the maximum temperature under which the testwill run, and Temperature Min is the minimum temperature desired for thetest to run. The user can set the desired temperature range via thegraphical user interface, or by typing in the values.

[0054] An exemplary induced test setup screen shot is shown in FIG. 6.The induced test tests the insulation of the transformer. Here the userpreferably applies double the voltage, and simultaneously doubles thefrequency. If the frequency is not doubled, then the magnetic field willbe too large and the transformer will be ruined, so in order to keep alow magnetic field, the frequency is preferably at least doubled whendoubling the voltage.

[0055] The test voltage is a user chosen constant multiplied by therated voltage. This number multiplies the rated voltage of thetransformer to get the desired test voltage.

[0056] Test duration is measured in cycles, with the range of the cyclespreferably between about 5200 and 9200. The user has the choice, and theentry can be made via the knob, the scroll bar, or by typing it in thebox below the knob, for example.

[0057] Ramp Up1, is similar to the Ramp Up1 in the applied test. Thevoltage increases at a rate specified by the user. This Ramp Up1 is thespeed at which the voltage increases to about 90% of the requiredvoltage. Ramp Up2 is the speed at which the voltage rises between about90% until it reaches the desired test voltage. The speed of Ramp Up2 ispreferably slower than that of Ramp Up1, so as to ensure a slow andaccurate approach to the high voltage. This is also set by the user.

[0058] The maximum and minimum temperatures for the operation of thetest are preferably set by the user. If the temperature is below theminimum, or higher than the maximum, the test will not be performed.

[0059] An exemplary load test setup screen shot is shown in FIG. 7. Theload test setup measures the load losses generated by current. The lowvoltage side is short-circuited and the voltage is raised on the highside to reach the rated current. The power is then measured, whichconfigures the load loss amount.

[0060] The user has the choice of performing the test under a currentthat is not the rated current, but rather a percentage of the nominalcurrent. The user can choose the desired percentage of the nominalcurrent.

[0061] The stability range is a percent of the test current. The currentis preferably stable for the test to be performed. The user has theability to choose the desired percentage of the test current, in orderfor the test to remain stable.

[0062] The nominal tap is the tap at which the voltage is the testvoltage itself. The user can choose a tap, where each tap is a certainpercentage of the test voltage, hence the user can choose a tapaccording to the desired voltage. For example, if a tap is set to 2.5%,then the voltage would become 2.5% of the test voltage. Selecting thehighest tap is useful if the whole winding is to be tested.

[0063] T ref is the user selectable reference temperature to which thetemperature in the load loss can be compared. The maximum and minimumtemperatures are the endpoints of the range in between which the testcan run. These temperatures are user selectable.

[0064] An exemplary magnetizing current test setup screen shot is shownin FIG. 8. A high voltage is applied on the high side of the transformerin order to demagnetize it. The low side is not short-circuited. Themagnetizing current test is to demagnetize the core, by applying a highvoltage on the high side of the transformer.

[0065] The user can choose the voltage applied on the high side of thetransformer by selecting the voltage, e.g., by moving the knob,scrolling the scroll bar, or typing in the required value. 380V is atypical amount that is applied on the high side in this circumstance,but a range is provided. The stability range is a percentage of the testvoltage, and is user selectable.

[0066] An exemplary megger test setup screen shot is shown in FIG. 9.The megger test is an insulation test with a relatively low applied DCvoltage. The user gets the result as a resistance value. Test voltagecan be set by the user, and it is the relatively low DC voltage appliedbetween the bushings and the ground. The user can select the desiredvoltage, e.g., by moving the knob, or scrolling the scroll bar, ortyping it in. Regarding test duration, the user preferably has a choicebetween 0 and about 300 seconds for the length of the test.

[0067] Measurements of the resistance can be taken at any point in timethat the user desires. The polarization index is the number the usergets by dividing the resistance value at, for example, 60 seconds by theresistance value at, for example, 15 seconds. The user chooses the timevalues at which the resistance is to be measured and the polarizationindex, though optional, will be determined in accordance with the user'stime entries.

[0068] The time at which the resistance will be measured can be set viaa scroll bar or other input devices. The user can add as many times asdesired. The maximum and minimum temperature under which the test willtake place can also be set by the user.

[0069] An exemplary no load test setup screen shot is shown in FIG. 10.The no load loss is the power in the magnetic field also called ironloss. Power is applied to the low voltage side so that the magneticfield is under normal operation, and the power is then measured.

[0070] The test voltage here is a percent of the nominal voltage. Theuser can choose the percentage of the nominal voltage desired to beapplied. The range for the percentage is between about 70% and about110%.

[0071] The stability range is user selectable and is a percent of thetest voltage, which runs from about 1.0 to about 5.0. If the box near“correct” is checked, then the user has the ability to set his owntemperature reference. If, on the other hand, this box is not checked,then the T ref. will gray out, and the reference temperature will be setautomatically, so the user will not have the ability to set it. T ref.is the reference temperature that the user goes by in order to maintaina fixed variable throughout testing. It is the temperature to which theno load loss can be compared.

[0072] The maximum and minimum temperatures for the test to run arepreferably user selectable. The test will run as long as the temperaturethrough out the testing remains in between the maximum and the minimumtemperatures.

[0073] An exemplary ratio test setup screen shot is shown in FIG. 11.The ratio test tests the ratio to be fixed according to the taps. Forexample, if tap 1 is set to 5% and the user chooses tap 1, then theratio increases by 5%. Taps tested shows the taps that have been enteredby the user, and these taps will undergo the test.

[0074] The delete button deletes any unwanted taps that have alreadybeen added. This may be done, for example, by highlighting the unwantedtap, and clicking the delete button. If the “all” box is checked, thenall the taps will be selected, and the user will not have access toadding or deleting.

[0075] The maximum and minimum temperatures are the limits between whichthe test temperature lies. If the test temperature exceeds the maximum,or is below the minimum, then the test will not run. The user can setthe desired maximum and minimum temperatures.

[0076] An exemplary resistance test setup screen shot is shown in FIG.12. The resistance test measures the three connected windings of thetransformer to determine whether they have the same resistance. Apercentage of the rated current can be set. The user can choose the testcurrent to be between about 1% and about 10% of the value of the ratedcurrent.

[0077] T ref. is the reference temperature to which the temperature iscompared in order to keep a fixed variable. It is the temperature atwhich the resistance can be compared. The user can set this temperatureas desired.

[0078] The taps that will undergo the testing are displayed. IECstandards can be applied to any of the taps. If the user checks the IECbox, then the test is performed in accordance with IEC standards.

[0079] After creating the transformer test sequence, the user or atester can open the test sequence using the test sequence engine and runit. The test sequence engine performs the tests in the test sequence andprovides an indication of the test results and any system messages, suchas error messages and status of the testing. FIG. 13 is an exemplarytest engine screen shot in accordance with the present invention.

[0080] The engine performs all the tests in the test sequence in theorder they are in and with the test parameters in the sequence. Theengine communicates with the test equipment such as power supplies andmeasurement instruments. It also loads the transformer specificationsand pass/fail criteria from a database (e.g., memory device 115 in FIG.1). Preferably, the engine determines a pass/fail criteria for everytest and determines a test result for the overall test sequence.

[0081] The test sequence engine can also operate on dual and triplevoltage transformers. It can accommodate as many as six high and lowvoltage combinations. The test sequence engine allows the tester tomonitor the progress of a test sequence and the results of the testswith a detailed subscreen. It also allows the tester to monitor thehardware status and hardware related errors. The test sequence enginefurther allows the operator to turn off a certain test. This is usefulif the tester decides to skip certain tests in the test sequence,without modifying the test sequence using the test sequence editor.

[0082] The test instructions or the pre-existing sequence of testinstructions selected are retrieved from a memory device such as thememory device 115 or memory 113 located within the CPU 111. The CPU 111also retrieves the transformer specifications from the memory device115. The CPU 111 executes the test program by sequentially executingeach of the test instructions in the test program, starting with thefirst test instruction in the sequence and ending with the last testinstruction in the sequence. The sequence of test instructions may berepresented by a stream of data or a list of test instructions. Whileexecuting the test program, the CPU 111 generates a test result whichtypically indicates whether or not the transformer passes the testprogram. Pass/fail is determined on the transformer being tested basedon database parameters or standards. The test result is displayed on thedisplay device 114.

[0083] If a certain test fails during the test sequence, the testsequence may be aborted, either manually by an operator monitoring thetesting or automatically by the system if the testing criteria have beenprogrammed to abort in such a case. The test engine keeps track of unitspreviously tested. Previous test results are accessible from the memorydevice 120 or wherever the results may be stored.

[0084] Preferably, the operator can cancel tests even though they arepart of the test sequence. This is desirable in the case in which atransformer is retested and some tests are not required.

[0085] Some transformers have up to three high voltage sides and up totwo low voltage sides. The test engine desirably deals with these unitsas six separate units to account for all the combinations. The systempreferably keeps track of the pass/fail status of each one of them. Acombination can be assigned a test sequence different from the testsequence of the other combinations.

[0086] The user may customize the test-program by selecting the desiredtest instructions and/or pre-existing sequence of test instructions andthen defining the order of execution of each of the test instructionsselected by inputting entry commands into the processor 110 via a userinterface. In one embodiment of the present invention, the user mayinteract with the processor through a Windows 2000 graphical userinterface manufactured by Microsoft. However, the present invention mayalso be implemented using other operating systems such Windows NT andMac O/S. Thus, with the use of an input/output device such as a keyboardor mouse, the user selects the test instruction or sequence of testinstructions desired. The user can also defines the order of executionby placing each selected test instruction in the correct location in thesequence which may be represented by list or a stream of testinstructions. Thus, the processor sequentially executes each testinstruction starting with the first test instruction in the list orstream and ending with the last test instruction in the list or stream.

[0087] By allowing the user to customize test programs via the userinterface, the user has the flexibility of optimizing each test programfor his particular needs. For example, if a user finds it advantageousto reduce the test time for a transformer, he/she may customize a testprogram to perform those test instructions or subsequences of testinstructions most likely to cause a failure first.

[0088] The tests available to the user either control some aspect of thehardware or process data. For example, if a megger test subsequence isspecified by the user in the test program, then the processor 110 sendsa series of commands to the controller 130 to run a megger test on thetransformer. When executing each sequence, each test instruction eithercauses the hardware to perform some function or process data during theexecution of the test.

[0089] With respect to the engine shown in FIG. 13, “CT” refers to thecurrent transformer tap, and “PT” refers to the potential tap, both ofwhich are user selectable. The step up tap is the transformer's currentposition. The output mode is also provided.

[0090] In an embodiment, there are three decks in the switching network,and there are five taps. In such an embodiment, in each deck, theswitching network is in one of the five positions, and the position isshown in the area below the deck number.

[0091] The megger switch indicates to the user if it is on, off, or ifthere is an error. The visual disconnect indicator indicates whether thepower supply is activated. If the shorting switch is turned on, the lowside of the transformer is shorted.

[0092] The resistance H switch is the resistance on the high side of theresistance switch, and indicates whether or not the resistance H switchis deactivated. The resistance L switch is the resistance on the lowside of the resistance switch, and indicates whether or not theresistance L switch is deactivated.

[0093] An indicator also is provided that indicates whether or not theoutput of the power supply is energized. Also, an indicator is providedthat indicates whether an emergency circuit is activated.

[0094] If an error occurs, an indicator is preferably activated, and anexplanation is desirably presented in a text box. For example, if thewattmeter is not responding, a lamp ill turn red, and in the text box astatement will appear informing the user of the error.

[0095] In this example, there are six combinations of the transformer,which has up to three on the high voltage side and up to two on the lowvoltage side. Each combination runs through the test sequence. Accordingto the sequence, in FIG. 13, the combination will be tested on the ratiotest first, then on the resistance test, etc., and finally the meggertest. When the test sequence changes, so does the order of the testingof the combination.

[0096] The test results are also provided (e.g., on another screen (notshown)). For the applied test, the side of the test, High or Low, ispresented. The Vt, which is the test voltage, and the status of thetest, whether it passed, failed, or had an error occur, are presented aswell. The applied test for each combination presents here the side ofthe transformer being tested [Side], the test voltage [V test, in kV forexample], the current [I, in mA for example] and the status which showswhether the test passed, failed or whether an error occurred.

[0097] For the magnetizing current test, the test voltage is statedbeneath Vt, the current is presented beneath ‘I’, and the statusindicates to the user whether the test passed, failed, or whether anerror occurred.

[0098] For the induced test, the test voltage [Vt] is shown, and thecurrent [I] is presented, and the status of the test, whether pass,fail, or error, is displayed in a status box. The induced test summaryin this embodiment shows the test voltage [V test], the current [I] andthe status, which determines whether the test passed, failed, or had anerror occur.

[0099] For the megger test, the user will see the test Voltage [Vt], andthe corresponding side, whether High to Ground, Low to Ground, or Highto Low. The status of each of these will be presented as pass, fail, orerror if an error occurred. During the megger test, the user will seethe duration, the side which is whether it is the High and groundconnected to the Low [HG], or the High and the Low connected to theground [HL]. The test voltage [Vt] and the status of either side,whether it passed, failed, or whether an error occurred, are alsoindicated.

[0100] The losses tests are shown individually in FIG. 13, under No loadloss and Load loss. When the combination reaches this test it goesthrough the one represented first in the sequence. In this case, it isthe load loss, and while the test is being done the user can see thetest voltage [Vt], the transformers impedance [Imp] and the status,which states whether the test failed passed or had an error occur in it.The no load loss test shows the test voltage and the status when thecombination is being tested there. The load loss test presents the userwith the following information, while the test is being undergone: Thereference temperature, the voltage, the three phases of the current, thepower corrected, the status of the power, the impedance corrected, andthe status for the impedance. The no load test shows the measured power,which the user wants to see in the no load loss test, the correctedpower, the status of the power, that shows whether it passed, failed, orhad an error. It also presents the user with the current phases 1, 2 and3, as well as the average of the current phases in percentage, and thestatus of the current, that shows the test status of passing, failing,or having had an error.

[0101] While the ratio test is being performed on the combination, theuser can see which tap the test is at, and the corresponding status. Thestatus tells the user if the test has failed, passed, or if an erroroccurred on each particular tap. The ratio test shows the tap, the threephases of the current, phase 1, phase 2, and phase 3. The phases of theratios are also presented. The test does not undergo any two of thesesimultaneously, but rather shifts form one to the other one step at atime. The phase angles are presented to the user as well, and show howmuch the phases are shifted with respect to each other, so there arethree phase angles.

[0102] For the resistance test, the user views which tap the test isrunning through, and the corresponding status. The status tells the useris the test has failed, passed, or if an error occurred on eachparticular tap.

[0103] The temperature at which the test is running is also provided.Recall that the user set the maximum and minimum temperatures of thetests in the sequence. This temperature should lie in between themaximum and minimum temperatures that were set for each particular testindividually. If the temperature is higher than the maximum, or lowerthan the minimum, the test will not take place.

[0104] System messages can also be provided that present the user withmessages on the status of the tests, presenting the errors and the timesat which they occurred. The messages are displayed, for example, tellingthe user the status of the test, when it is beginning to be tested, ifit was completed successfully, or whether an error occurred. The time isdesirably presented also so that the user knows what time an erroroccurred or a test started, what time it ended, or what time an erroroccurred. The system messages can be provided, e.g., on another screen(not shown).

[0105] The user can also select tests in the sequence to disable orenable. If all the tests are switched off then no test will be takeneven if it is present in the test sequence. So the user has the abilityto turn any test off, even if it is present in the test sequence, andnot allow it to run and hence the test will not be taken. If all thetests are turned on, then only the ones present in the test sequencewill run.

[0106] The invention may be embodied in the form of appropriate computersoftware, or in the form of appropriate hardware or a combination ofappropriate hardware and software without departing from the spirit andscope of the present invention. Further details regarding such hardwareand/or software should be apparent to the relevant general public.Accordingly, further descriptions of such hardware and/or softwareherein are not believed to be necessary.

[0107] Although illustrated and described herein with reference tocertain specific embodiments, the present invention is nevertheless notintended to be limited to the details shown. Rather, variousmodifications may be made in the details within the scope and range ofequivalents of the claims without departing from the invention.

What is claimed:
 1. A system for testing a transformer comprising: aprocessor comprising a transformer test engine adapted to execute atransformer test sequence; a controller coupled to the processor tooutput control commands; a switcher coupled between the controller andthe transformer to switch power to the controller responsive to thecontrol commands; and a metering system coupled between the transformerand the processor to receive measurements from the transformer andprovide the measurements to the processor.
 2. The system of claim 1,further comprising a memory device coupled to the processor for storingtransformer specifications.
 3. The system of claim 1, further comprisinga memory device for storing the transformer test sequence.
 4. The systemof claim 1, wherein the processor further comprises a test sequenceeditor to allow customization of the transformer test sequence.
 5. Thesystem of claim 4, further comprising an input device for receivingcommands into the test sequence editor.
 6. The system of claim 1,wherein the transformer test sequence comprises a plurality of testinstructions and associated parameters.
 7. A method for testing atransformer comprising: connecting the transformer to a processorcomprising a transformer test engine; loading a customized transformertest sequence into the processor; and executing the customizedtransformer test sequence with the transformer test engine.
 8. Themethod of claim 7, further comprising: providing results of theexecution to the processor; providing transformer specifications to theprocessor; and determining whether the transformer passes responsive tothe results and the transformer specifications.
 9. The method of claim8, further comprising activating an indicator responsive to the step ofdetermining.
 10. The method of claim 8, further comprising storing theresults in a memory device.
 11. The method of claim 7, furthercomprising receiving the customized transformer test sequence prior toloading.
 12. The method of claim 7, wherein executing the customizedtransformer test sequence comprises sequentially executing a pluralityof test instructions with associated parameters until one of the end ofthe sequence is reached and an abort command is received.
 13. A methodfor creating or editing a customized transformer test programcomprising: selecting at least one test instruction or pre-existingsequence of test instructions from a plurality of transformer testinstructions; providing at least one associated parameter for each ofthe selected test instructions or pre-existing sequence of testinstructions; and defining an order of execution of each of the testinstructions.
 14. The method of claim 13, further comprising storing theorder of execution of each of the test instructions.
 15. The method ofclaim 13, further comprising executing the test instructions inaccordance with the order.
 16. The method of claim 13, furthercomprising receiving an input command, and wherein the step of selectingis performed in response to the input command.
 17. The method of claim13, further comprising generating a transformer test sequence based onthe order.
 18. A computer readable medium having computer-executableinstructions for performing the steps comprising: selecting at least onetest instruction or pre-existing sequence of test instructions from aplurality of transformer test instructions; providing at least oneassociated parameter for each of the selected test instructions orpre-existing sequence of test instructions; and defining an order ofexecution of each of the test instructions.
 19. The computer readablemedium of claim 18, having further computer-executable instructions forstoring the order of execution of each of the test instructions.
 20. Thecomputer readable medium of 18, having further computer-executableinstructions for executing the test instructions in accordance with theorder.
 21. The computer readable medium of 18, having furthercomputer-executable instructions for receiving an input command, andwherein the step of selecting is performed in response to the inputcommand.
 22. The computer readable medium of 18, having furthercomputer-executable instructions for generating a transformer testsequence based on the order.
 23. In a computer implemented device havinga computer readable storage medium having computer executablecomponents, the computer executable components comprising: a data storefor storing a transformer test sequence comprising a plurality oftransformer tests to be performed on a transformer by a transformer testengine; and a processor for reading the transformer test sequence anddirecting the transformer test engine to operate in accordance with thetransformer test sequence.
 24. The device of claim 23, wherein the datastore further stores transformer specifications.
 25. The device of claim23, wherein the processor further receives commands for creating andediting the transformer test sequence.
 26. The device of claim 23,wherein the transformer test sequence comprises a plurality of testinstructions and associated parameters.